Sure, if you can grow that subset to 100% then you can keep all the pizza for yourself, but the reason tech salaries are so high is the companies are that profitable.
If Zuckerberg is paying Alabama rates to everyone, it will be trivially easy to poach talent from him, and he knows this, so while he might have in mind a pool of "superfungibles" making $ALABAMA in $WHEREVER, you will not see Big Tech start slashing the compensation of the people they want to keep.